Shell construction sealing washer

ABSTRACT

1. A gun launched ram jet projectile having a warhead assembly and an attached shell structure mounted within a cartridge casing, the combination comprising an explosive charge within an inner casing supported centrally within an outer casing and spaced therefrom to provide an air passage therebetween, a tubular solid fuel grain fitted in the inner wall of said shell structure and axially spaced from said inner casing, said grain defining a combustion chamber, an aluminium ring having a central opening substantially the same diameter as the central longitudinal bore of said tubular grain cemented to said inner casing and axially spaced therefrom when in a closed position, said ring when in said closed position sealing said air passage to prevent escape of fuel gases while said shell is in a gun barrel, and to move axially to an open position against said grain in response to air pressure during free flight of said projectile to provide passage of said air to said combustion chamber.

I Unite States atent 91 Squiers SHELL CONSTRUCTION SEALING WASHER [75]Inventor: John C. Squiers, Grosse Pointe Woods, Mich.

[73] Assignee: The United States of America as represented by theSecretary of the Army, Washington, DC.

[22] Filed: Aug. 26, 1955 21] Appl.l lo.: 530,921

[52] U.S. Cl. 102/38; 102/49.3; 60/270 S [51] Int. Cl. F423 9/10 [58]Field of Search 102/49, 92.5, 38, 49.3; 60/270 [56] References CitedUNITED STATES PATENTS 1,994,490 3/1935 Skinner lO2/49.2 2,684,629 7/1954Nordfors 60/270 S Primary ExaminerVerlin R. Pendegrass Attorney, Agent,or Firm-Nathan Edelberg; Robert P. Gibson 5 7 ABSTRACT 1. A gun launchedram jet projectile having a warhead assembly and an attached shellstructure mounted within a cartridge casing, the combination comprisingan explosive charge within an inner casing supported centrally within anouter casing and spaced therefrom to provide an air passagetherebetween, a tubular solid fuel grain fitted in the inner wall ofsaid shell structure and axially spaced from said inner casing, saidgrain defining a combustion chamber, an aluminium ring having a centralopening substantially the same diameter as the central longitudinal boreof said tubular grain cemented to said inner casing and axially spacedtherefrom when in a closed position, said ring when in said closedposition sealing said air passage to prevent escape of fuel gases whilesaid shell is in a gun barrel, and to move axially to an open positionagainst said grain in response to air pressure during free flight ofsaid projectile to provide passage of said air to said combustionchamber.

6 Claims, 5 Drawing Figures PATENTED SEP 9 I975 .E E R1... m: m M m ID61A n 1 m J B/ E NCQ Q SHELL CONSTRUCTION SEALING WASHER This inventionrelates to anti-aircraft projectiles having a shorter time of flight andhigher striking velocity than heretofore and in particular to agun-launched solid-fuel ram-jet-propelled projectile.

Much difficulty has been experienced in sealing off the projectile fueland the front-entering air passages in ram jet projectiles until afterthe projectile is in flight and in particular preventing escape ofpropellant gases while the projectile is in the gun barrel. When theprojectile has left the gun barrel the air passages must be opened toallow air to reach the fuel. Heretofore, due to the complex nature ofthe valves used for this purpose they have not performed satisfactorilyin that they did not respond quickly enough to flight condition of theprojectile and because of a time lag in readily supplying air for thefuel upon launching of the projectile.

Therefore, it is one object of this invention to provide a simple andefficient air sealing aluminum ring cemented to the rear wall of thewarhead which requires no adjustment and which operates in response toair pressure created by the flight of the projectile to instantaneouslyallow air, in sufficient quantity, to reach the fuel for combustion.

It is another object of this invention to provide a simple air sealingaluminum washer for a ram jet projectile which in open position allowsair to reach the fuel without travelling an unduly tortuous path.

Another object of this invention is to provide a simple air sealingmechanism which requires no adjustment for a ram jet projectile in whichthe propellant is ignited by the gun blast, thus eliminating the need ofa separate igniter.

Another object of this invention is to provide a ram jet projectile thatdoes not require other than normal handling precautions, has a simpleair sealing mechanism and utilizes a solid fuel as a propellant.

Another object of this invention is to provide a ram jet fuel whichburns uniformly, produces higher thrusts and lower burning rate than thesimple magnesium fuels.

Another object of this invention is to provide a projectile of the ramjet type in which the fuel is in the shape of a hollow cylinder cementedto the shell body. This allows the shell walls to be insulated by thefuel until the fuel is burned, thus precluding the possibility of thetailpipe of the shell burning off during flight. A further object ofthis invention is to provide a ram jet projectile in which the explosivecharge is carried forward in the center section of a supersonic diffuserand in which a point detonating fuze is built into the point of thediffuser.

For a more detailed understanding of the invention reference may be hadto the accompanying drawing illustrating a preferred embodiment thereofin which like characters refer to like parts throughout the severalviews and in which,

FIG. 1 is a longitudinal sectional view of the ram jet projectileshowing the sealing ring in open" position.

FIG. 2 is a somewhat enlarged detailed sectional view of the warheadassembly showing the washer cemented to the rear wall of said warheadand closing the internal air passages thereof.

FIG. 3 is a traverse sectional view taken on line 3-3 of FIG. 1,

FIG. 4 is a traverse sectional view taken on line 44 of FIG. 1, and

FIG. 5 is a detail perspective view of the aluminum sealing ring orwasher.

The gun-launched ram-jet projectile as hereinafter described comprises awarhead assembly A and a shell structure B which is permanently attachedor otherwise secured to the warhead assembly, preferrably by means of ascrew threaded joint as at 10. The warhead carries an explosive charge11 within a casing 12 supported within the outer casing 13 of thewarhead assembly in such a way as to provide air passage 14. The rearwall 15 of said warhead assembly solidly secures the outer casing 13 tothe casing 12 and is provided with air passages 16 communicating withpassage 14. The rear wall 15 is also provided with a rotating ring 18 atthe periphery thereof.

The shell structure B has cemented to the interior wall thereof a hollowcylindrical solid fuel grain 17 and the forward end or upstream end ofthis grain terminates short of the rear wall 15 of the warhead as shownin FIGS. 1 and 2 which provides a cylindrical space 19 of an axiallength greater than the axial thickness of the sealing ring 20 which islocated in such space 19. Preferably this space 19 is about two or threetimes longer than the axial thickness of the sealing ring. It will be observed in FIG. 1 that the central opening in the sealing ring isapproximately the same diameter as the internal bore diameter in thesolid fuel grain and that the combustion chamber is defined by the fuelgrain.

A suitable rubber cement is utilized to cement one face of the sealingring to the rear wall 15 of the warhead (see FIG. 2) and thus theinterior of the shell is effectively sealed as the sealing ring orwasher 20 closes the openings or air passages 16.

The gun blast charge 24 used to launch the projectile is contained inthe cartridge 25. The gun blast is also utilized to act as an igniterfor the propellant by heating it to a suffieient temperature.

The solid fuel grains utilized as the propellant are simple magnesiumfuels containing magnesium, oxidizer and binder to which has been addedsmall amounts of stearic acid or magnesium stearate as an internallubricant when the fuel was pressed. By adding the stearic acid a moreuniform burning with higher thrusts is obtained over simple magnesiumfuels. In addition the stearic acid fuels have a lower burning rate thanthe simple magnesium fuels.

In operation the projectile is ejected from the casing 25 by the gunblast 24 and at the same time the propellant 17 is heated to ignitiontemperature. The high pressures built up within the bore of the grainand chamber 19 by the gun blast is rapidly dissipated when theprojectile leaves the gun barrel. Due to this pressure the sealing ringis firmly held in place against the high initial force of acceleration,and upon the projectiles emergence from the gun bore at muzzle velocityand rapid dissipation of gun blast pressure the ram air pressure on theforward side of the sealing ring is sufficient to snap the ring backagainst the forward end of the grain, allowing instantaneous and fullair flow to the propellant which is already at ignition temperature. Thesealing washer is held in its open position by ram air pressure, theforce of acceleration as well as pressures generated by the burning fuelsince the sealing ring is up against the grain prior to orsimultaneously with air being supplied to the fuel. As a result all thegas pressures built up in chamber 19 tend to force the sealing ringagainst the grain and hold it there.

It will be apparent to those skilled in the art to which this inventionrelates that various changes and modifications may be made hereinwithout departing from the spirit of the invention as defined in theappended claims.

I claim:

1. A gun launched rarn jet projectile having a warhead assembly and anattached shell structure mounted within a cartridge casing, thecombination comprising an explosive charge within an inner casingsupported centrally within an outer casing and spaced therefrom toprovide an air passage therebetween, a tubular solid fuel grain fittedin the inner wall of said shell structure and axially spaced from saidinner casing, said grain defining a combustion chamber, an aluminiumring having a central opening substantially the same diameter as thecenter longitudinal bore of said tubular grain cemented to said innercasing and axially spaced therefrom when in a closed position, said ringwhen in said closed position sealing said air passage to prevent escapeof fuel gases while said shell is in a gun barrel, and to move axiallyto an open position against said grain in response to air pressureduring free flight of said projectile to provide passage of said air tosaid combustion chamber.

2. In a gun launched ram jet projectile comprising a warhead assemblyprovided with longitudinally extended air passages, a shell structureattached to said warhead assembly and carrying a hollow cylindricalshaped solid fuel grain cemented to the interior shell surface, saidfuel grain longitudinally spaced from the rear wall of said warheadassembly, and a sealing washer displaceably disposed in the shellstructure in the space between said fuel grain and the rear wall of saidwarhead assembly, said sealing washer initially cemented to the saidrear wall of the warhead assembly to close said air passages, the spacebetween the fuel grain and the rear wall of the warhead assembly beinggreater than the axial thickness of said sealing washer, whereby uponlaunching of said projectile, the increase of air pressure in saidwarhead air passages displaces said sealing washer and opens said airpassages to provide air for the burning of the fuel in said shellstructure.

3. In a gun launched ram jet projectile comprising a warhead assemblyprovided with longitudinally extended air passages, a shell structureattached to said warhead assembly and carrying a hollow cylindricallyshaped solid fuel grain cemented to the interior shell surface, saidfuel grain longitudinally spaced from the rear wall of said warheadassembly and a sealing washer displacably disposed in the shellstructure in the space between said fuel grain and the rear wall of saidwarhead assembly, said sealing washer initially cemented to the saidrear wall of the warhead assembly to close said air passages, the spacebetween the fuel grain and the rear wall of the warhead assembly beinggreater than the axial thickness of said sealing washer, whereby uponlaunching of said projectile the increase of air pressure in saidwarhead air passages displaces said sealing washer and opens said airpassages to provide air for the burning of the fuel in said shellstructure, said sealing washer comprising an aluminum ring structurehaving a central opening substantially the same diameter as the centrallongitudinal opening in said hollow cylindrically shaped solid fuelgrain.

4. The device as in claim 3 in which the space between said fuel grainand rear wall of said warhead assembly is two to three times longer thanthe axial thickness of said sealing washer.

5. In a gun launched ram jet projectile comprising a warhead assemblyprovided with longitudinally extended air passages, a shell structureattached to said warhead and carrying a hollow cylindrically shapedsolid fuel grain cemented to the interior shell surface, said fuel grainlongitudinally spaced from the rear wall of said warhead assembly, and asealing washer disposed in the shell structure in the space between saidfull grain and the rear wall of said warhead assembly, said sealingwasher initially cemented to the said rear wall of the warhead assemblyto close said air passages, the space between the fuel grain and therear wall of the warhead assembly being greater than the axial thicknessof said sealing washer, whereby upon launching of said projectile, theincrease of air pressure in said warhead air passages displaces saidsealing washer and opens said air passages to provide air for theburning of the fuel in said shell structure, said sealing washercemented to the rear wall warhead structure by a rubber cementpermitting same to be detached in response to Y a relatively slightpressure rise in said air passages of about 25 pounds per square inch.

6. In a gun launched ram jet projectile the combination of a warheadassembly, a shell structure attached 'to and spaced from said warheadassembly, said shell structure being mounted within a cartridge casing,said warhead assembly comprising an explosive charge within an innercasing supported centrally within an outer casing and spaced therefromto provide an air passage therebetween, a point detonating fuze mountedon the forward end of said inner casing and an aluminum sealing ringcemented to the rear wall of said inner casing to seal off said airpassages, a cylindri cal stearic acid magnesium fuel grain cemented tothe inner wall of said shell structure and spaced from the rear wall ofsaid inner casing, defining a sealing ring cylinder within which saidsealing ring moves from a closed position in which it is cemented to therear wall of the inner casing to an open position in which it restsagainst said grain, said grain defining a combustion chamber within thecentral bore thereof which is supplied with air under pressure from saidair passages when said sealing ring is in said open position in responseto ram air pressure, a gun blast charge within said cartridge casing tolaunch said warhead assembly and attached shell structure.

1. A gun launched ram jet projectile having a warhead assembly and anattached shell structure mounted within a cartridge casing, thecombination comprising an explosive charge within an inner casingsupported centrally within an outer casing and spaced therefrom toprovide an air passage therebetween, a tubular solid fuel grain fittedin the inner wall of said shell structure and axially spaced from saidinner casing, said grain defining a combustion chamber, an aluminiumring having a central opening substantially the same diameter as thecenter longitudinal bore of said tubular grain cemented to said innercasing and axially spaced therefrom when in a closed position, said ringwhen in said closed position sealing said air passage to prevent escapeof fuel gases while said shell is in a gun barrel, and to move axiallyto an open position against said grain in response to air pressureduring free flight of said projectile to provide passage of said air tosaid combustion chamber.
 2. In a gun launched ram jet projectilecomprising a warhead assembly provided with longitudinally extended airpassages, a shell structure attached to said warhead assembly andcarrying a hollow cylindrical shaped solid fuel grain cemented to theinterior shell surface, said fuel grain longitudinally spaced from therear wall of said warhead assembly, and a sealing washer displaceablydisposed in the shell structure in the space between said fuel grain andthe rear wall of said warhead assembly, said sealing washer initiallycemented to the said rear wall of the warhead assembly to close said airpassages, the space between the fuel grain and the rear wall of thewarhead assembly being greater than the axial thickness of said sealingwasher, whereby upon launching of said projectile, the increase of airpressure in said warhead air passages displaces said sealing washer andopens said air passages to provide air for the burning of the fuel insaid shell structure.
 3. In a gun launched ram jet projectile comprisinga warhead assembly provided with longitudinally extended air passages, ashell structure attached to said warhead assembly and carrying a hollowcylindrically shaped solid fuel grain cemented to the interior shellsurface, said fuel grain longitudinally spaced from the rear wall ofsaid warhead assembly and a sealing washer displacably disposed in theshell structure in the space between said fuel grain and the rear wallof said warhead assembly, said sealing washer initially cemented to thesaid rear wall of the warhead assembly to close said air passages, thespace between the fuel grain and the rear wall of the warhead assemblybeing greater than the axial thickness of said sealing washer, wherebyupon launching of said projectile the increase of air pressure in saidwarhead air passages displaces said sealing washer and opens said airpassages to provide air for the burning of the fuel in said shellstructure, said sealing washer comprising an aluminum ring structurehaving a central opening substantially the same diameter as the centrallongitudinal opening in said hollow cylindrically shaped solid fuelgrain.
 4. The device as in claim 3 in which the space between said fuelgrain and rear wall of said warhead assembly is two to three timeslonger than the axial thickness of said sealing washer.
 5. In a gunLaunched ram jet projectile comprising a warhead assembly provided withlongitudinally extended air passages, a shell structure attached to saidwarhead and carrying a hollow cylindrically shaped solid fuel graincemented to the interior shell surface, said fuel grain longitudinallyspaced from the rear wall of said warhead assembly, and a sealing washerdisposed in the shell structure in the space between said full grain andthe rear wall of said warhead assembly, said sealing washer initiallycemented to the said rear wall of the warhead assembly to close said airpassages, the space between the fuel grain and the rear wall of thewarhead assembly being greater than the axial thickness of said sealingwasher, whereby upon launching of said projectile, the increase of airpressure in said warhead air passages displaces said sealing washer andopens said air passages to provide air for the burning of the fuel insaid shell structure, said sealing washer cemented to the rear wallwarhead structure by a rubber cement permitting same to be detached inresponse to a relatively slight pressure rise in said air passages ofabout 25 pounds per square inch.
 6. In a gun launched ram jet projectilethe combination of a warhead assembly, a shell structure attached to andspaced from said warhead assembly, said shell structure being mountedwithin a cartridge casing, said warhead assembly comprising an explosivecharge within an inner casing supported centrally within an outer casingand spaced therefrom to provide an air passage therebetween, a pointdetonating fuze mounted on the forward end of said inner casing and analuminum sealing ring cemented to the rear wall of said inner casing toseal off said air passages, a cylindrical stearic acid magnesium fuelgrain cemented to the inner wall of said shell structure and spaced fromthe rear wall of said inner casing, defining a sealing ring cylinderwithin which said sealing ring moves from a closed position in which itis cemented to the rear wall of the inner casing to an open position inwhich it rests against said grain, said grain defining a combustionchamber within the central bore thereof which is supplied with air underpressure from said air passages when said sealing ring is in said openposition in response to ram air pressure, a gun blast charge within saidcartridge casing to launch said warhead assembly and attached shellstructure.